The determination of individual moral status is a central factor in the ethical evaluation of controversial practices such as elective abortion, human embryo-destructive research, and the care of the severely disabled and those in persistent vegetative states. A review of recent work on Kant reveals the need for a careful examination of the content of Kant’s biological and psychological theories and their relation to his views about moral status. Such an examination, in conjunction with Kant’s practical-metaphysical analysis of the origins of freedom, reveals Kant’s principled basis for his contention that all human beings possess moral status.